The Invertebrate Fauna of the Uitenhage Series. 149 



and its carina falls more steeply and forms a line more nearly 

 straight. In Trapezium ? tatei, the carina follows a more oblique 

 direction and forms a more curved line when the valve is viewed 

 in lateral aspect. In Corbula ? rockiana the umbonal region is 

 broader and more massive, and the incurvation more pronounced. 

 It may be remarked that Tate's figure of Corbula ? rockiana is not 

 accurately drawn. The figure gives the idea that there is a depres- 

 sion or concavity on the surface of the valve, whereas this is really 

 not the case in the specimen itself. 



A shell of apparently very similar type, so far as external 

 characters go, has been described by G. Miiller* from the Lower 

 Cretaceous of German East Africa as Mactra stromeri. Another 

 comparable form when large specimens are selected is Mactra ? angu- 

 lata J. de C. Sowerby, from the Blackdown Beds of England.! This, 

 however, is less produced in front and the umbonal region is 

 not so prominently developed and is less incurved. The umbo in 

 Trapezium ? tatei is more anteriorly placed and more forwardly 

 directed. 



Owing to the scanty material available for study, and the fact that 

 the nature of the interior is at present unknown, the generic position 

 of this shell cannot be satisfactorily settled, although the provisional 

 assignment to Trapezium may, perhaps, not prove incorrect. It 

 seems possible, however, that this may be a member of the group, 

 typified by Cypricardia bathonica d'Orb.,| of the Great Oolite, for 

 which Fischer has proposed the name Pseudotrapezium,^ although 

 there can be no certainty on this point. 



GENUS CYPEINA Lamarck. 

 CYPRINA EUGULOSA Sharps. 



1856. Gyprina rugulosa D. Sharpe, Trans. Geol. Soc. Lond., ser. 2, 

 vol. vii., p. 195, pi. xxii., fig. 9. 



Occurrence. This characteristic form was obtained from the green 

 sandy beds, crowded with the remains of oysters, in the cliff below 

 the old school-house at Dunbrodie, Sunday's Kiver (325). Sharpe 

 recorded it from " Sunday Eiver, in greenish shelly grit," and Stow 

 mentions its occurrence above the Modder Drift on the Sunday's 



* G. Miiller (1), p. 563, pi. xxv., fig. 15. 

 f J. de C. Sowerby (2), p. 341, pi. xvi., fig. 9. 

 J Morris and Lycett (1), part ii., p. 75, pi. vii., fig. 8 (1853). 

 Fischer (1), fasc. xi., p. 1075 (1887i. 

 11 



